Ahh, funny you should bring up the Bowser example. When I was watching the stream, I can see the character is definitely better, but something didn't feel complete about him.
The Bowser I've been working on feels more like Project M Bowser than his melee counterpart. He is very slightly faster (1 frame faster jump, 1-4 frames less lag on aerials and a couple attacks), as I wanted to keep the character true to his style. The main differences is are that I chose to make him 15% bigger, with his hitboxes scaled up, slightly heavier with a better recovery, and more power as well. And also a few more subtle things like increasing the duration the hitbox is active on a move or two. Recently, I gave him a pseudo superarmor on a few of his attacks and jump; that is a couple frames of invulnerability like Yoshi's parry. I haven't tested this change against actual players but I feel it would be appropriate and keep him true to his slow, tankish character.
One aspect I don't think people have experimented with is animation swapping. You can do some interesting things to a characters move set and I've done this for several poor moves on certain characters.
For float data, I have a lot of data gathered but it's incomplete. I am pretty lazy with it. I don't usually complete all the floats for each character (there are alot more than meets the eye), but just look for the ones for something I want to change (ie side B), so I don't usually delve into the floats unless I actually want to change them.
Do you update the floats on the wiki at all? I can share what I have that isn't on there if you'd like.